The present invention relates to an IC card reader/writer, and in particular, to an IC card reader/writer in which an electric circuit configuration to prevent a destruction of an IC card is integrated.
IC cards have been used for various purposes, for example, as a credit card. As the IC cards become to be broadly used, there has arisen a problem that the IC card is destructed because of various causes such as a static electric noise of a plastic used as a material of the IC card and a latch-up phenomenon due to an insufficient contact between the IC card and an IC card reader/writer.
Various countermeasurements have been devised to protect an integrated circuit (to be abbreviated as an IC herebelow) against the static electric noise of the plastic material; however, it has been difficult to prevent the latch-up phenomenon occurring in a complementary metal oxide semiconductor (MOS) predominantly used for the IC cards. The latch-up phenomenon is a phenomenon in which the signal input voltage of an IC card exceeds the power supply voltage and the IC chip is destroyed when the electric contact between the IC card and the IC card reader/writer is unstable.